The invention is directed to an automatic feeder for strip-supported electrical components and its method of operation, and in particular for supplying discrete components from a supply of components supported from a continuous strip for pickup by any one of conventional pick-and-place machines.
Pick-and-place machines are well known and widely used in the populating of printed circuit boards or cards (PCBs) by components using surface mount technology (SMT). They offer the capability of precision in component placement, and speed in picking up a component from its source and placing it typically on a solder-paste covered pad on the PCB. Often the components are removed from small receptacles on a tape carrier. Nowadays, however, components are often supplied on a strip unreeled from a reel supplied to the PCB maker by the component supplier. U.S. Pat. No. 5,605,430 describes a feeder actuated by a pick-and-place machine for components connected to each other at their base to form a strip, which patent disclosure is hereby incorporated by reference. With this strip of components such as pins or posts, the beveled end of the pin or post which is adapted to be picked up the conventional vacuum nozzle of a standard pick-and-place machine, is positioned above its base and thus the beveled pickup end rises free of the base and free of adjacent components and when separated from its neighbor is ready for pickup. However, some suppliers supply components suspended by their beveled pickup end from a common carrier. In this case, the beveled pickup end is obstructed by the carrier. Moreover, even if the component can be separated from its carrier, the carrier may obstruct the vacuum nozzle when it arrives to pickup the separated component. The feeder described in U.S. Pat. No. 5,605,430 is incapable of feeding such a strip of components for automatic pickup by pick-and-place machines.
A principal object of the invention is an automatic feeder for components suspended from a common carrier for pickup by a conventional pick-and-place machine.
A further object of the invention is a low cost high speed automatic feeder compatible with various pick-and-place machines and easily capable of feeding various diameters and lengths of components such as pins or posts to the pick-and-place machine.
Still another object of the invention is a method of separating components from a strip of components and making them available for pickup by a conventional pick-and-place machine.
These objects are achieved in accordance with one aspect of the invention by a novel feeder construction that is easily interfaced to a variety of conventional pick-and-place machines and can readily and reliably feed components suspended from a common carrier after separation for pickup by the pick-and-place machine. In the context of this application, the term xe2x80x9csuspendedxe2x80x9d when employed in relation to the carrier, means that the components are supported from above by the carrier, or the components hang from and below the carrier. In a preferred embodiment, the carrier with suspended components is fed along a path spaced laterally from the location where the component must be placed to be picked up by the descending pickup arm of the pick-and-place machine. The lead component when separated from the strip must then be moved laterally to the pickup location. By laterally spacing the carrier strip of components from the pickup location it is ensured that the feeder parts involved in separating the component from the carrier and carrying the separated component to the pickup location do not obstruct movement of the vacuum nozzle of the pick-and-place machine during the pickup operation nor advancement of the carrier to supply the next component.
In accordance with another feature of the invention, the feeder parts that separate the lead component from the carrier and move it to the pickup location comprise a component-retaining means having a clamping surface and means for temporarily holding the separated component against the clamping surface between the time that the component is separated and the time that it is ready for pickup. The timing of the feeder operation is controlled such that the holding means releases the component and the element forming the clamping surface is moved away from the pickup location before the pickup arm with the engaged component departs the pickup location.
In accordance with still another feature of the invention, the feeder parts are arranged such that the part that actually separates the lead component from the carrier accomplishes this by engaging the component near where it is connected to the carrier while simultaneously the part forming the clamping surface also engages a portion of the component further removed from its connection to the carrier to ensure a clean shearing without bending of the component from the carrier.
As still another feature of the invention, the component-separating means comprises means for straightening the components on the strip before they have reached the separation position.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components.